Whenever Kate Middleton’s brother-in-law comes to America, he gets his party on, and that’s exactly what he’s been doing in Miami!

We spotted the young prince poolside (above), showing off his hard work at the gym! And even though he just split from Cressida Bones, the 29-year-old isn’t gaining any breakup weight.

An eyewitness talked about Harry’s gym routine, saying:

"Harry was at the gym at 6 p.m., working out with his trainer Winston [Squire]. He'd spent the day at the Invictus Games selection event, and was still wearing his Invictus T-shirt. He'd even brought a sweatshirt for his trainer with Invictus on it, which he handed over at the end of his workout."

Another onlooker said:

"He didn't look down or depressed at all. He was laughing and joking with his trainer like he usually does and had a big smile on his face."

So, what part of his bod is Harry most concerned about? His midsection! Just like any other human being! An insider previously explained:

"Harry says he finds it really hard to shift weight round his middle, so that's his main aim. Other than that, he just wants to increase his fitness. At the moment he's mainly been doing circuit-style training but he's been in the boxing room, and his trainer is getting him ready to start some sparring."

Oh, so circuit training and boxing is all that we have to do to get a royalphysique, huh?!

Well, it's clearly working for Harry! If only his trip could be longer!